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created ZSTD_format declaration

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Yann Collet 2017-09-21 16:07:29 -07:00
parent bdc83f523b
commit f97c2dbd39
2 changed files with 18 additions and 4 deletions
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3
NEWS
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@ -3,7 +3,8 @@ new : long range mode, using --long command, by Stella Lau (@stellamplau)
license : changed /examples license to BSD + GPLv2
license : fix a few header files to reflect new license (#825)
fix : multi-threading compression works with custom allocators
fix : a rare compression bug when compression generates very large distances (only possible at --ultra -22)
fix : ZSTD_sizeof_CStream() was over-evaluating memory usage
fix : a rare compression bug when compression generates very large distances and bunch of other conditions (only possible at --ultra -22)
fix : 32-bits build can now decode large offsets (levels 21+)
cli : new : can split input file for dictionary training, using command -B#
cli : fix : do not change /dev/null permissions when using command -t with root access, reported by @mike155 (#851)

19
lib/zstd.h
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@ -927,14 +927,27 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
* The main driver is that it identifies more clearly the target object type.
* It feels clearer in light of potential variants :
* ZSTD_CDict_setParameter() (rather than ZSTD_setCDictParameter())
* ZSTD_DCtx_setParameter() (rather than ZSTD_setDCtxParameter() )
* Left variant feels easier to distinguish.
* ZSTD_CCtxParams_setParameter() (rather than ZSTD_setCCtxParamsParameter() )
*/
/* note on enum design :
* All enum will be manually set to explicit values before reaching "stable API" status */
typedef enum {
ZSTD_f_zstd1, /* Normal (default) zstd frame format, as specified in zstd_compression_format.md */
ZSTD_f_zstd1_magicLess, /* Almost zstd frame format, but without initial 4-bytes magic number */
ZSTD_f_zstd1_headerless, /* Almost zstd frame format, but without any frame header;
* Other metadata, like block size or frame checksum, are still generated */
ZSTD_f_zstd_block /* Pure zstd compressed block, without any metadata.
* Note that size of uncompressed block must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB.
* See ZSTD_compressBlock() for more details. */
} ZSTD_format;
typedef enum {
/* compression format */
ZSTD_p_format = 10, /* See ZSTD_format enum definition.
* Cast selected strategy as unsigned for ZSTD_CCtx_setParameter() compatibility. */
/* compression parameters */
ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
* Default level is ZSTD_CLEVEL_DEFAULT==3.
@ -1216,7 +1229,7 @@ ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams(
+ compression : any ZSTD_compressBegin*() variant, including with dictionary
+ decompression : any ZSTD_decompressBegin*() variant, including with dictionary
+ copyCCtx() and copyDCtx() can be used too
- Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX
- Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB
+ If input is larger than a block size, it's necessary to split input data into multiple blocks
+ For inputs larger than a single block size, consider using the regular ZSTD_compress() instead.
Frame metadata is not that costly, and quickly becomes negligible as source size grows larger.